The work and pensions secretary accused David Cameron, George Osborne and the
in campaign of 'pessimistic downsizing' in a row over the EU referendum vote

Iain Duncan Smith has suggested the Prime Minister, as leader of the in campaign, has a "low opinion of the British people" in a thinly-veiled personal attack over the UK's membership of the EU.

The Work and Pensions Secretary warned his leader against telling people that leaving the EU would be a "leap into the dark" and instead claimed it would be a "stride into the light".

In an interview with the BBC's Andrew Marr Mr Duncan Smith launched a series of deeply personal criticisms in defence of his position as a campaigner for Brexit.

Mr Duncan Smith said his is positive about the case for leaving the EU Photo: Geoff Pugh

Asked about the possibility of economic shocks if Britain leaves the European Union, he said: "I say this to those who say they want to remain in, I have never heard such a lot of pessimistic downsizing on Britain's aspect.

"Britain is a phenomenal country, the fifth largest in the world, it has stood alone and fought for freedom, it has traded, it is a global trader ...it can yet again be a global trader."

The Prime Minister has allowed his senior colleagues to speak out against his reforms Photo: GETTY

And in a comment aimed at Mr Cameron and Mr Osborne, who have both warned against a "leap into the dark" and the possibility of "profound economic shocks" if the UK votes to leave, Mr Duncan Smith added: "Why would we have such a low opinion of the British people that we go out and talk about leaping into the dark and profound shocks?

"We talk about not being capable and we're too small. Well I have a different view, my view is Britain is a great country, the people here are inventive and innovative and they will find a way with us to actually have a real deal to give Britain access to the world and access to Europe."

The country will vote on the relationship of the EU in June Photo: ALAMY

He also warned of "great scare stories put out by the in people" and took aim at Mr Cameron for seeking to persuade people not to leave the EU with claims about lost trade.

Cautioning his own colleagues not to "play the person, play the ball", he added: "This is not about personalities, the in camp, whose strategy seems to be about "oh its terrible, hang on to your nerves", ... it's been about saying we're too small, we're too little, we're too inconsequential, we cant do what we want ... I don't know why anyone would want to run a country like this.

"This country is the greatest country on earth, not because it's the biggest or the strongest, but because it has the most brilliant people."

Mr Johnson has also come out for Brexit Photo: PAUL GROVER

The work and pensions secretary is one of the most senior Conservatives in the Prime Minister's cabinet, but he is also one of the strongest proponents of leaving the EU.

Speaking about the need to get a better deal for the UK financial services industry, Mr Duncan Smith said Britain would do a trade deal with the EU if voters backed a Brexit.

He warned European Union nations would not reject such an agreement because it is in their interests to continue to trade with the UK.